Conventionally, in a situation in which a source device, a switch device, and a sink device are connected by a high speed wire interface, in order to view contents of a specific source device in the sink device, a switch process of input ports of the switch device and/or the sink device is required. In this case, when the source device is directly connected to a high speed wire interface device of the sink device, a user switches the input port of the sink device to the input port to which the source device is connected. When the sink device is indirectly connected to the source device through a device (e.g., AVR) that performs a repeater function or the switch device connected to the high speed wire interface device of the sink device, the user should switch an input port of the switch device or the repeater device to an input port to which the source device is connected and switch the input port of the sink device to the input port to which the switch device or the device that performs a repeater function is connected. There is a problem that the user should individually switch the input port of each device.
In order to enhance the problem, in a conventional HDMI system, when the user activates a source device to use, a specific command is transmitted to a sink device through a CEC protocol, and a function of switching to a corresponding input port is provided to the sink device and thus it is unnecessary that the user switches an input port. However, there is a problem that the user should activate a corresponding source device with a remote control and that a separate remote control should be used at every source device, when a plurality of source devices exist. Further, there have been many cases that an input port switch function does not well operate due to instability of a CEC bus.